Introduction
The aims of this work is to investigate the performance and stability of the water current Catamaran Turbine Prototype. There are three aspects to be considered in designing process hydrostatic, stability, and performance of floating hydroenergy generator to generate power. CFD analysis conducted to investigate the flow around Catamaran and rotating turbine. The flow stream around Catamaran has oscillated moment and force and these could affect the stability. The model of buoyancy device was produced and tested in water flume. The test result shows that buoyancy device has good stability, it may be seen from the ability of the buoyant to keep its position when there is a disturbance on stability.
The Catamaran Buoyancy Device
The Similarity Principle
The Similarity Principle
Scaling method to scale down the protoptype to the model use the Pinumber of the Buckingham theorem, The law approach can be derives as follows : 1). To define the Law can represents the phenomenon occurs, 2). To simplify the formulation of the law, 3).To make the formulation to the non dimensional parameter.
Table 3 Scale Parameters between model and prototype
Geometry
Λ= Time 1/ Λ1/2=2.93/1
Acceleration of Gravity 1 Displacement Λ=1/8.6
Mass
Λm = Angle of Rotation 1
Mass Moment of Inertia Λm*Λ2= 1/40834 Velocity Λ1/2=1/2.93
Specific Thrust Λm/Λ2=1/8.6 Acceleration 1
Specific Impulse Λm/ Λ3/2=1/25.22 Angular Velocity 1/ Λ1/2=2.93/1
Coefficient of Friction 1 Angular Acceleration 1/ Λ=8.6/1
The Initial Catamaran Model Stability
The model submersed in an water is subjected to an upward force equal to the weight of the displaced fluid. The center of buoyancy calculate from the bottom of the Catamaran model, in the transversal direction.
The Righting Arm
The righting arm is the displacement of the center of buoyancy due to the change of line action of the buoyancy force intersection when angle of heel to starboard change.
Buoyancy body inclined The curve of righting arm versus angle of heel
The Wind Heeling Arm
The stability of the Catamaran model has to be investigates due to the side wind. That is a wind perpendicular to the Center Line plane.
Wind Heeling Arm Curve of Wind Level Arm
Streamline and velocity contour around Catamaran at 1.5 m/s and 100 rpm
Conclusion
Model Test of the Water Current Catamaran Turbine and Their
Stability
Priyono Sutikno, Rafil Fikriyan
Faculty of Mechanical and Aeronautical Engineering, Institute Technology Bandung,
CFD Simulation Flow around the Turbine Catamaran
Acknowledgment
This work supported in part by Research Fund from New and Renewable
Energy Research Center LPPM ITB 2014 (Institute Technology Bandung) Indonesia .
Center Of Gravity (COG) 163 mm
Center Of Buoyancy(COB) 175 mm
BM Transversal 181 mm BM Longitudinal 101 mm
Metacenter Transversal (KM) 356 mm
Metacenter Longitudinal (KM) 276 mm
GM Transversal 193 mm GM Longitudinal 113 mm Position of Meta-center (C), Center of
Buoy-ancy (B), Center of Gravity (A)
References
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2. Priyono Sutikno, Yuliandra Syahrial Nurdin, Doddy Risqi, Eki Mardani, Erpinus
Sihombing. Experimental of Three Parallel Water Current Turbine With Optimized Straight Blades And Using Flow Concentrator Channeling Device To
Augmented Performance and Self Starting Capability.Applied Mechanics and
Materials Vol 758 (2015) pp 153-158 © (2015) Trans Tech Publications, Switzerland, doi:10.4028/www.scientific.net/AMM.758.153
